What theory behind this ?

[quatumrulesoverall]

What is the theory behind the vibration of wire generated by an magnetic field and a electric current ?

[Titas Aduksus]

Do you mean as in a guitar pickup?

[quatumrulesoverall]

I m not referring to musical instrument. I meant when a current run through the wire located in a magnaetic field, by what theory that makes it vibrate ?

[Erasmus00]

I m not referring to musical instrument. I meant when a current run through the wire located in a magnaetic field, by what theory that makes it vibrate ?

 

Electromagnetic theory can describe the force on the wire. Mechanical/elastic theory can describe the resulting vibration/waves in the wire.

-Will

[quatumrulesoverall]

could you be more specific about the electromagnetic theory?

[Erasmus00]

could you be more specific about the electromagnetic theory?

 

Standard Maxwell electrodynamics. The force on the wire is specifically the Lorentz force.

-Will

[Pyrotex]

could you be more specific about the electromagnetic theory?

Alternating current through the wire--that's the secret.

 

A wire with a DC current has a static magnetic field. If there is an external magnetic field then they will pull/push on each other just as ordinary metal magnets will. The wire will be pushed, let's say, to the left.

 

Then the current in the wire switches the other way, which reverses the wire's static magnetic field. The wire will be pushed/pulled in the opposite direction, against the external magnetic field which has not changed. Use AC in the wire, and the wire will go back and forth at the same rate as the frequency of the AC. If you are using 60 Hz current, then the wire will emit what we know as "60 cycle hum". Change the frequency of the AC current and change the pitch of the wire's hum.

 

This works the same if the wire has a constant DC current and the external magnetic field is alternated.

[quatumrulesoverall]

Great thanks to you all